Up to 70 percent of the human body consists of water. It is present on both the inside and outside of the cells.
Water or fluid retention refers to an excessive buildup of fluid in the circulatory system, body tissues, or cavities in the body.
It can occur in many different areas of the body and for different reasons. This MNT Knowledge Center article will look at the causes of water retention in each area individually.
Fast facts on water retention:
Up to 70 percent of the body is made of water.
Symptoms of water retention include stiff joints and skin discoloration
Treatment includes diuretic pills and keeping the legs raised 3 to 4 times a day.
Symptoms will occur in the affected area in which water is being retained.
These symptoms include:
areas of skin that stay indented when pushed in with a finger, known as pitting edema
aches and tenderness in the limbs
stiffness in the joints
Water retention is possible when the pressure inside blood vessels changes.
Fluid rich in nutrients, vitamins, and oxygen continuously passes from tiny blood vessels into surrounding tissues. This fluid is known as interstitial fluid.
Interstitial fluid nourishes cells and eventually makes its way back to the capillaries. Water retention may occur if the pressure inside the capillaries changes.
Water retention is also possible if the capillary walls become too leaky. If something goes wrong with pressure or the wall becomes too leaky, excess liquid will be released into the spaces between cells.
If too much fluid is released, more of it will remain in the tissues, rather than returning to the capillaries, resulting in swelling and water retention.
The lymphatic system
The lymphatic system drains a fluid called lymph from tissues and empties it back into the bloodstream. However, if too much fluid is released in the first place, the lymphatic system can become overwhelmed. It is unable to return fluid fast enough, and this builds up around the tissues.
Sometimes, if the lymphatic system is congested, the rate at which fluid is returned to the bloodstream may change. This means that fluid might remain in the tissues, causing swelling in various parts of the body, including the abdomen, ankles, legs, and feet.
Normal pressure within blood vessels is partly maintained by the pumping force of the heart. However, if the heart starts to fail, there will be a change in blood pressure, which often results in serious water retention.
Typically, the legs, feet, and ankles will swell. Fluid will also build up in the lungs, giving the patient a long-term cough or breathing difficulties.
Congestive heart failure can eventually cause breathing problems, as well as excessive stress on the heart.